A terror test for Gordon and Dave

Mr Brown might also quietly reflect that the bombers did his Britishness crusade a service by reminding us, Scots Nats and all, that we are all in this together since the bombers took no account of the border.

Jacqui Smith as Home Secretary — a shrewd appointment — is rightly praised for her cool and factual approach, as her shadow David Davis generously observed in his own Commons statement on Monday.

The change of tone — away from the "war on terror" and towards an emphasis on common criminality — has advantages.

It does not get backs up unnecessarily. It is easy to be stoical, though, when no one has been killed and the only serious injuries are to one of the bombers themselves. Mr Brown and his team may have had a baptism of fire, but they — and we — got away lightly.

Mr Brown's aim, his aides say, is a "hearts and minds" battle for moderate Islam inside Britain and abroad. He underlined the stylistic break with the allor-nothing rhetoric of Mr Blair. But how different is he really? Already he has signalled that he intends to return to a bill for something pretty close to the last attempt to introduce 90 days' maximum terror detention without trial, one of the issues where feeling runs highest about the potential for unfair detention of Muslim suspects.

He is, I am told, convinced that in rare cases where evidence is hard to assemble and the security risks are deemed great enough, 90 days is the period worth fighting for. The Conservatives still disagree: though I notice that George Osborne and others are starting to use phrases such as "not set in stone" if new supporting evidence for a change is produced.

They will certainly be in a sticky position if the threat continues at present levels or worse and they tie themselves too firmly to the existing 28-day limit, when it is widely known that Michael Howard was preparing to do a deal for around 40 days, only to back off when Mr Blair's own intransigence looked set to cost him the vote. Both sides have played politics here. One will finally lose..

Critics will point out that terror detention would not probably not have made a difference this time, since the suspects were "clean skins". True. But effective prevention is about closing all possible gateways to violence, not the ones in front of us at any given time.

To this end, Mr Brown must also revisit the issue which most frustrated Mr Reid and Mr Clarke, namely the refusal of the judges to allow derogation from the Human Rights Act when it comes to deporting terror suspects to countries where they could face torture or ill treatment.

The balance of risk to righteousness is invidious here. The Government can seek reassurances from countries who have a less humane approach to terror suspects than the UK. But the legal ruling that refused to balance the rights of foreign-born terror suspects against the possible harm they might do by remaining in Britain flies in the face of reason as well as public confidence.

Control orders, the unsatisfactory outcome of another Government-Judiciary stand off are a disaster — seven have been flouted to date since the Law Lords ruled against indefinite detention for foreign suspects who refuse to return home. It is no good the civil rights lobby claiming that the authorities should produce their evidence in front of a court. This is not Cluedo. The events of the past week give us an inkling of how far things can go before any reliable evidence is available.

So where will Jack Straw, as the new Justice Secretary, come down as he forges his Brownite constitutional settlement? How far the new Government goes in pursuing derogation from the relevant parts of the Human Rights Act will be a guide to the new PM's real instincts. It would also test Mr Cameron, who has fudged the matter with a call for a British bill of rights yet been evasive on the HRA for fear of unleashing his Right wing.

The other open loophole is Pakistan and the relative ease with which Britishborn Asians are able to travel to and from a country which, together with neighbouring Afghanistan, is providing most of the off-the-peg terror training for young British jihadis.

On all these matters, the Prime Minister's commitment to a new tone will soon come under more probing glare. The same questions should sharpen Conservative focus at a time when Mr Cameron needs to show that he has the leadership skills and the intellectual weight to take on Mr Brown. In Dame Pauline

Neville-Jones, his new security spokesman in the reshuffle, he has a senior Whitehall figure of calibre. Her critics would say that her record has been on advising caution about the radical ideas of others.

That is not the same as gauging the wisest response to events where the parties must also show that they are connected to the public's concerns. To her credit, she has pursued the case for using intelligence intercepts in court, an argument which Mr Brown is on the verge of publicly adopting and led the way in outing the equivocal stance of extremism of some Muslim organisations.

She is also said to favour ID cards, which will produce a clash with shadow Home Secretary David Davis. The trouble with appointing knowledgeable outsiders, as both party leaders will find, is that they come with some troublesome ideas, beyond the ones they like.

Sayeed Warsi, the first woman Muslim parliamentary candidate promoted to a peerage, is another visible appointment which shows Mr Cameron's eye for fresh talent and clever orchestration of his newcomers. A new focus on Muslim community issues will throw open some questions the New Conservative political establishment has largely avoided: not least the most productive ways to ensure moderate Muslims can prosper and feel at home in Britain, while playing their vital part in identifying and combating extremists.

Neither party can escape the challenges to their comfort zones of a threat which is here for the long-term. The botched bombers have sewn much anxiety and stress. They have also done us a favour by asking us, once again, what we really think is valuable and how we intend to protect it. As Mr Brown and Mr Cameron are about to find out, terrorists have a habit of showing us what our politicians are really made of..